rlackore

If you're referring to using the Wall Specification dbx General>General>Terrain Retaining Wall checkbox, then yes.

Before you change the wall type or definition, set The Resize About to Main Layer Inside.

Turn off "Use Special Snapping"

I am unfamiliar with Home Designer Suite. If you are planning on using 24' manufactured trusses, then the out-to-out dimension between the exterior wall framing should be 24'. For purposes of truss design, 99% of the time you will ignore everything (sheathing, siding, etc.) beyond the outside face of the framing (wall studs).

Just curious. What is the advantage to this strategy? What problem does it solve that an invisible wall does not?

You can assign a Molding to a Shelf; however, the Molding will "wrap" at a free end, as shown in the picture, so unless the shelf butts against a wall, it will look weird in 3D, unless you add an invisible wall to make the "wrap" disappear. Assign a molding: Molding "wraps" at free end: Unless you place an Invisible Wall:

Typically, roof trusses span between the outside faces of the exterior wall framing (wall studs/plates). In the Wall Specification dbx, the value reported in General>General>Thickness includes all the Wall Layers, regardless of whether they are Exterior Layers, Main Layers, or Interior Layers. If you want to dimension to the outside face of the framing, define the wall with Wall Type Definitions>Wall Properties>Wall Settings>Dimension to Exterior of Layer set to the Main Layer component that defines the wall framing. Also, pay attention to the Dimension Defaults settings within the Default Set you are using.

You could define the balcony as a Deck, build the framing, then delete the rim board:

Here's one method to make a hole: 1. Shoot an Elevation camera view and draw your desired polygon. Then use the Convert Polyline tool to turn it into a 3D Solid with a thickness greater than the wall thickness (though technically the thickness doesn't matter, it can help visually when placing in the wall). Here's what you get: 2. Select the solid and turn it into a Symbol. Select a type of Symbol that allows the option "Inserts into Wall" (very important), such as Exterior Fixture: 3. Place the symbol on the wall and set its insert depth great enough to completely cut a hole through the full depth of the wall: 4. Return to the Elevation view, select the Symbol, and use the Edit Wall Cutout Polyline tool to adjust the cutout shape to match the symbol. 5. Assign a transparent material to the Symbol and you've got a hole in the wall:

Actually, the window IS cutting the upper wall, but the lower wall has been "dragged" up to overlap the upper wall; so, what you're seeing is the lower wall occluding the window and the tall garage door. Select the lower wall and tick the checkbox Wall Specification>Structure>Default wall Heights>Default Wall Top Height.

You can find the lintel symbols in the Library Browser: Chief Architect Core Catalogs>Architectural>Millwork>Keystones>Bottom At least, that's where they are found in versions X15 and X16; probably in earlier versions also, but I only have X15 and X16 installed.

Post the plan?

Uncheck this option, maybe.

One possibility: